Electric motor



June 23, 1936. c. DDDD UTTER 2,045,218

Fi l e d O G t l 5 l 9 35 Patented June 23, 1936 ELECTRIC moron Charlesnutme London, England Application October 15, 1985, Serial No. 45,148 InGreat Britain October 22, 1934 2 Claims. (01. 2-36) This inventionrelates to electric motors for rotary tool devices carried and appliedby hand such as electric drills or the like.

According to the invention the electric motor in such hand-carried andapplied portable electric tools has a horse-shoe field magnet andwinding removable as a unitary structure from the casing of the motor,the winding being provided with integral or fixedly associated contactelements to co-operate. preferably by spring pressure, with othercontacts located within the said casing and enclosed thereby so as tomake electrical connection with said contact elements when the saidhorse-shoe magnet and winding are inserted into position in the casingand break such electrical connection on the removal of the horse-shoemagnet and winding.

Thus the horse-shoe field magnet with its single or multiple windings,readily can be mounted or dismounted into or out of position,

and when so mounted the winding or windings.

automatically are connected to and remain, in the essential circuit orcircuits. In this manner, the necessity for soldering or otherwiseconnecting the winding or windings oi the horseshoe field magnet to theother part of the circuit or circuits is avoided and consequentlyassembly is facilitated and necessary repairs or replacements carriedout with great expedition. j

As will be realized, the invention may be" carried into effect in manyways and the drawing illustrates one method only. I

In the drawing, a hand-applied portable drill adapted to be supported byhand in the manner has a somewhat horse-shoe shaped field magnet havingassociated therewith a single winding.

P18. 1 is a front elevation otthe tool with the casing partly brokenaway and with the revealed portion partlyin section, whilst Fig. 2 is aperspective view of the detached unitary structure comprising the fieldmagnet with its winding and contacts.

' In the drawing 3 is-Vthe outer main casing which has mounted therein,in any usual manner, the armature" 4 with which co-operates the fieldmagnet shown detached in Fig. 2.

This latter comprises a somewhat horse-shoe shaped laminated fieldmagnet proper I having 55 The upper and lower halves of these enlargeota pistol is shownxthe electric motor of which a yoke i surrounded by thetwo halves l 01' a ments on each'sideand at the ends are formed withrecesses bounded by undercut dovetail edges. Each pair oi these recesseshouses a contact making plate 9 oi suitable metal having dovetail edgesengaging the edges of the recesses,

. as shown. To these plates the ends of a winding l0 located around thespool and yokes are electrically connected, for exampleby soldering. v

The unitary structure shown in Fig. 2 and comprising the complete fieldmagnet system is 10 the casing 3.

When so mounted the contact plates 9 are pressed into contact withco-operating contact members suitably carried in the casing and con- 15nected to the inner circuit or circuits. Such contacts are illustratedin Fig. .1 by a springpressed pin II and a spring strip l2. It will berealized that in place of the structure described,

suitably mounted within, and held in position in the contact. plates,such as 9, may be replaced 20 by springy contacts to co+operate withspring or other contacts.

Further in place of the particularv contact plates 8 such as shown andthe co-operating contact members, it will be realized that any other 5suitable forms of co-operating contacts may be utilized, provided theyautomatically make con tact when the winding is mounted in position andbreak the contact when-the winding is removed. v 80 Although in theparticular example illustrated only a single winding has been shown, itis obvious that more than one winding may be utilized. Further, wheremore than one winding is included each winding may have its own con- 35tacts, or the whole oi. the windings or groups of them may be associatedwith particular contacts.

Similarly although only one field magnet is shown, any suitable andrequired number of field magnets may be utilized. 40

The invention is not limited to the precise forms or details orconstruction described, as these may be varied to suit particular cases.

What I claim and desire to secure by Letters Patent 0! the United Statesof America isz electrical connection with said-contact elements 2 oi thewinding on insertion oi said unitary structure in position in the casingand to break such electrical connection on the removal of said unitarystructure, for the purposes set iortli.

2. An electric motor for a. rotary tool device carried and applied byhand, having a. casing,

an armature in said casing, a horse-shoe field magnet and windingremovable from said casing as a. unitary structure independently of thearmature, contect elementseiectricelly connected m to and m fixedassociation with said. winning,

other contacts located within said casing and enclosed thereby adaptedto make electrical connection with said contact elements of the windingon insertion of said unitary structure in po-e sitlon in the casing andto break such electrical connection on the removal of said unitarystructure and. spring pressure means to maintain the electricalconnection between the parts when the unitary structure is inposition inthe casing,

(CHARLES DESOU'I'I'ER.

